基于双阈值的压缩采样匹配追踪改进算法

针对基于压缩感知的压缩采样匹配追踪(CoSaMP)算法迭代次数严重依赖于信号稀疏度,候选原子冗余度大,从而导致最终的支撑原子集选择时间长、选择精度低等问题,提出一种基于双阈值的压缩采样匹配追踪算法.该算法利用模糊阈值进行支撑集候选原子的选择,引入残差与观测矩阵的相关度变化阈值作为迭代停止条件,对图像进行重构.仿真实验表明,所提出的算法重构速度快,重构效果优于CoSaMP算法.     

改进的压缩采样匹配追踪算法

针对压缩采样匹配追踪( CoSaMP)算法重构精度相对较差的问题,为了提高算法的重构性能,提出了一种基于伪逆处理改进的压缩采样匹配追踪( MCoSaMP)算法。首先,在迭代前,对观测矩阵进行伪逆处理,以此来降低原子间的相干性,从而提高原子选择的准确性;然后,结合正交匹配追踪算法( OMP),将OMP算法迭代K次后的原子和残差作为CoSaMP算法的输入;最后,每次迭代后,通过判断残差是否小于预设阈值来决定算法是否终止。实验结果表明,无论是对一维高斯随机信号还是二维图像信号,MCoSaMP算法的重构效果优于CoSaMP算法,能够在观测值相对较少的情况下,实现信号的精确重构。     

用于图像重构的基于行间支撑集相似度的CoSaMP算法

压缩采样匹配追踪(CoSaMP)算法的性能受初始支撑集选择的制约,初始支撑集选择不准确不仅影响重构精度,还会降低重构速度。针对该问题,将图像在稀疏域的结构特性引入到CoSaMP算法中,提出了支撑集相似度的概念;利用数字图像相邻行之间原子支撑集的相似性,提出了基于行间支撑集相似度的CoSaMP算法。实验结果表明,在同等采样率的条件下, 与传统的CoSaMP算法相比,所提算法在不增加算法时间复杂度的同时提高了重构质量 ,峰值信噪比提高了0.6~2.5dB。     

一种自适应正则化子空间追踪算法

针对压缩感知中未知稀疏度信号的重建问题,提出一种新的压缩感知的信号重建算法,即自适应正则化子空间追踪（Adaptive Regularized Subspace Pursuit,ARSP）算法,该算法将自适应思想、正则化思想与子空间追踪（Subspace Pursuit,SP）算法相结合,在未知信号稀疏度的情况下,自适应地选择支撑集原子的个数,利用正则化过程实现支撑集的二次筛选,最终能实现信号的精确重构。仿真结果表明,该算法能够精确重构原始信号,重建效果优于SP算法、正则化正交匹配追踪（ROMP）算法、稀疏度自适应匹配追踪（SAMP）算法、压缩采样匹配追踪（CoSaMP）算法等。     

一种新的跳频信号重构算法

为解决跳频信号压缩感知重构中稀疏度未知和稀疏字典规模庞大的问题,提出了一种基于多峰值匹配的压缩感知重构算法。该算法借鉴传统匹配追踪类算法结构,采用多峰值匹配原则进行原子选择,通过一次迭代确定候选集,然后利用回溯思想对候选集进行二次筛选获得支撑集,实现了跳频信号的精确重构。仿真结果表明,该算法重构性能与传统正交匹配追踪算法相近,同时重构速度大大提高。     

分段迭代匹配追踪图像重构算法

目的 压缩采样匹配追踪（CoSaMP）算法虽然引入回溯的思想,但其原子选择需要大量的观测值且在稀疏度估计不准确时,会降低信号重构精度,增加重构时间,降低重构效率。为提高CoSaMP算法的重构精度,改善算法的重构性能,提出了一种基于广义逆的分段迭代匹配追踪（StIMP）算法。方法 为保证迭代时挑选原子的精确性和快速性,对观测矩阵广义逆化,降低原子库中原子的相干性;原子更新结合正交匹配追踪（OMP）算法筛选原子的准确性与CoSaMP算法的回溯性,将迭代过程分为两个阶段：第1阶段利用OMP算法迭代K/2次;第2阶段以第1阶段OMP算法迭代所得的残差和原子为输入,并采用CoSaMP算法继续迭代,同时改变原子选择标准,从而精确快速地重构出稀疏信号。结果 对于1维的高斯随机信号,无论在不同的稀疏度还是观测值下,相比于OMP、CoSaMP、正则化正交匹配追踪（ROMP）算法和傅里叶类圆环压缩采样匹配追踪（FR-CoSaMP）算法,StIMP算法更加稳健,且具有更高重构成功率;对于2维图像信号,在各个采样率下,StIMP算法的峰值信噪比（PSNR）均高于其他重构算法,在采样率为0.7时,StIMP算法的平均PSNR值比OMP、CoSaMP、ROMP和FR-CoSaMP算法分别高2.14 dB、1.20 dB、3.67 dB和0.90 dB,平均重构时间也较OMP、CoSaMP和FR-CoSaMP算法短。结论 提出了一种改进的重构算法,对1维高斯随机信号和2维图像信号均有更好的重构效率和重构效果,与原算法和现有的主流图像重构方法相比,StIMP算法更具高效性和实用性。     

基于二次筛选的回溯广义正交匹配追踪算法的稀疏信号重构

压缩感知是一种新型的信号采样及重构理论,高效的信号重构算法是压缩感知由理论转向实际应用的枢纽。为了更精确地重构出原始稀疏信号,本文提出一种基于二次筛选的回溯广义正交匹配追踪算法。首先采用内积匹配准则选出较大数目的相关原子,提高原子的利用率。其次利用广义Jaccard系数准则对已选出的原子进行二次筛选,得到最匹配的原子,优化原子选取方式。实验结果表明,在不同稀疏度和观测值下进行信号重构,相比于回溯广义正交匹配追踪算法、正交匹配追踪算法及子空间追踪算法,本文算法在重构误差及重构成功率方面有较大的优越性。     

基于压缩感知的稀疏信道估计方法

针对OFDM系统中传统最小二乘(LS)信道估计方法需要大量导频估计精度却不高的问题,提出基于压缩采样匹配追踪(CoSaMP)的压缩感知信道估计新方法.利用发送信号,接收信号和信道的频城关系建立基于压缩感知的数学模型,再采用CoSaMP算法对信道进行重构.仿真结果表明,与LS算法相比,基于CoSaMP的压缩信道估计方法能利用少量的导频信号达到与之相比拟的信道估计性能,提高了频谱利用率;与现有压缩感知信道估计算法(基追踪(BP)与正交匹配追踪(OMP)相比,在使用相同导频数目条件下,具有更好的信道估计性能和更低的计算复杂度.     

基于小波树模型的CoSaMP压缩感知算法

无线传感网络存在网络带宽限制和传感器节点的能耗问题,实际应用中通常希望可以通过重构算法从采集的少量数据中还原出原始信息,压缩感知理论为上述问题提供了一个解决思路。利用压缩感知理论,对无线传感器网络中温度传感器的监测信号进行了压缩感知的应用研究。针对传统压缩采样匹配追踪(CoSaMP)算法中测量次数多、重构精度低等问题,利用信号的小波系数所形成的连通树的结构特性,提出了基于小波树模型的压缩采样匹配追踪算法。将该算法应用到无线传感器网络监测信号的压缩感知仿真实验中,与传统压缩采样匹配追踪算法的重构性能进行比较,结果表明该算法较传统压缩采样匹配追踪算法在一定范围内对无线传感器网络中的温度信号具有更好的压缩感知性能。     

基于压缩感知的CoSaMP算法自适应性改进

压缩感知重构算法在实际应用中需要预知信号稀疏度,而信号的稀疏度通常是未知的.为此,改进压缩采样匹配追踪(CoSaMP)算法的自适应性,提出一种稀疏度自适应贪婪算法.对信号稀疏度进行初始估计,结合SAMP算法思想,以残差值比对为终止条件,在CoSaMP算法框架下进行稀疏度逐步增大的递归运算,实现精确重构.仿真实验结果证明,该算法重构精度高、抗噪能力强,同时具备稀疏度自适应的特点.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.